1. Field of the Invention
This invention is in the area of measuring gas leakage past a barrier.
2. Description of the Prior Art
Gas leakage around or through a mine barrier has previously been determined. The U.S. Pat. No. 4,055,074 (Thimons et al) represents the closest known prior art concerned with the mining field. However, this prior art invention does not employ a tracer gas and as a result would not include most of the essential elements and steps herein claimed. The Thimons et al patent does teach the broad concept of setting up a test barrier near the mine stopping or barrier whose leakage is to be measured and then making measurements with an anemometer at various windows at the test barrier. These measurements may be at a single window or a combination of windows. Using the measurements and the principles of fluid dynamics, the total leakage past the permanent mine stopping is mathematically determined.
In contrast to the method disclosed in the Thimons et al patent, we employ a method for measuring leakage which utilizes a tracer gas and is as a result more accurate and capable of measuring much lower leaks. This is because direct measurement of air velocity is not necessary in a tracer gas method.
The prior art also teaches the concept of injecting a tracer gas into a vessel to determine the gas leakage therefrom. The three U.S. Pat. Nos. 3,425,264 (Frei), 3,487,677 (Molitor), and 3,721,117 (Ford) disclose this method. None are concerned with the mining field nor with the measurement of gas leakage past a mine stopping as set forth in our claims.